Bulk acoustic resonator, acoustic filter, and electronic device

An acoustic filter, comprising a plurality of cascaded bulk acoustic resonators, wherein the bulk acoustic resonator comprises:

• a piezoelectric material layer, an interdigital transducer, and a dielectric layer, wherein the interdigital transducer is disposed on the piezoelectric material layer, and the interdigital transducer comprises:
• a first busbar and a second busbar that are disposed opposite to each other;
• a plurality of first electrodes, wherein the plurality of first electrodes sequentially protrude from the first busbar to the second busbar along an extension direction of the first busbar;
• and
• a plurality of second electrodes, wherein the plurality of second electrodes sequentially protrude from the second busbar to the first busbar along an extension direction of the second busbar;
• the plurality of first electrodes and the plurality of second electrodes are sequentially arranged in a staggered manner between the first busbar and the second busbar;
• and
• the dielectric layer covers the piezoelectric material layer and the interdigital transducer, and thicknesses of a part, of the dielectric layer, located between at least one pair of adjacent first electrode and second electrode fluctuate.